Cyclic organosilicon compounds as electron donors for polyolefin catalysts

ABSTRACT

Cyclic organosilicon compounds that may be employed as an electron donor for polymerization catalyst systems, polymerization catalyst systems employing the cyclic organosilicon compounds as an electron donor, methods of making the polymerization catalyst systems, and polymerization processes to produce polyolefin are disclosed. The organosilicon compounds, which are useful as electron donors in polymerization catalyst systems for the production of polyolefins, are represented by the following formula: 
                         
wherein Q 1  and Q 2  may be identical or different and are each hetero-atoms selected from the group consisting of N, O, S, Si, B, and P, with the proviso that Q 1  and Q 2  cannot both be N or both be O. R 1  and R 2  may be identical or different and are each hydrocarbon-based substituents to Q 1  and Q 2 , respectively. The subscripts m and n are independently 0 to 3. R 3  is an aliphatic, alicyclic or aromatic group. R 4  is a hydrocarbon group with 1 to 6 carbon atoms. R 5  is a bridging group with a backbone chain length between the two hetero-atoms Q 1  and Q 2  being 1-8 atoms. The bridging group is selected from the group consisting of aliphatic, alicyclic, and aromatic bivalent radicals.

BACKGROUND

1. Field of the Invention

This invention relates to cyclic organosilicon compounds that may beemployed as an electron donor for polymerization catalyst systems, topolymerization catalyst systems employing the cyclic organosiliconcompounds as an electron donor, to methods of making the polymerizationcatalyst systems, and to polymerization processes to producepolyolefins, particularly polypropylene, having broadened molecularweight distribution employing the polymerization catalyst systems.

2. Description of the Related Art

Ziegler-Natta catalyst systems for polyolefin polymerization are wellknown in the art. Commonly, these systems are composed of a solidZiegler-Natta catalyst component and a co-catalyst component, usually anorganoaluminum compound. To increase the activity and sterospecificityof the catalyst system for the polymerization of α-olefins, electrondonating compounds have been widely used (1) as an internal electrondonor in the solid Ziegler-Natta catalyst component and/or (2) as anexternal electron donor to be used in conjunction with the solidZiegler-Natta catalyst component and the co-catalyst component.Organosilicon compounds are commonly used as external electron donors.

Common internal electron donor compounds, incorporated in the solidZiegler-Natta catalyst component during preparation of such componentinclude ethers, ketones, amines, alcohols, phenols, phosphines, andsilanes. Examples of such internal electron donor compounds and theiruse as a component of the catalyst system are described in U.S. Pat.Nos. 4,107,414; 4,186,107; 4,226,963; 4,347,160; 4,382,019; 4,435,550,4,465,782; 4,522,930; 4,530,912; 4,532,313; 4,560,671; 4,657,882;5,208,302; 5,902,765; 5,948,872; 6,121,483; and 6,770,586.

In the utilization of Ziegler-Natta type catalysts for polymerizationsinvolving propylene or other olefins for which isotacticity is apossibility, it may be desirable to utilize an external electron donor,which may or may not be in addition to the use of an internal electrondonor. It is known in the art that external electron donors act asstereoselective control agents to improve isotacticity, i.e.,stereoregularity of the resulted polymer products, by selectivelypoisoning or converting the active site of non-stereoregularity presenton the surface of a solid catalyst. Also, it is well known thatpolymerization activity, as well as stereoregularity and molecularweight and molecular weight distribution of the resulting polymer,depend on the molecular structure of external electron donor employed.Therefore, in order to improve polymerization process and the propertiesof the resulting polymer, there has been an effort and desire to developvarious external electron donors, particularly various organosilanecompounds. Examples of such external electron donors known in the artare organosilicon compounds containing Si—OCOR, Si—OR, or Si—NR₂ bonds,having silicon as the central atom, where R is commonly an alkyl,alkenyl, aryl, arylalkyl, or cycloalkyl with 1-20 carbon atoms. Suchcompounds are described in U.S. Pat. Nos. 4,472,524; 4,473,660;4,560,671; 4,581,342; 4,657,882; 5,106,807; 5,407,883; 5,684,173;6,228,961; 6,362,124; 6,552,136; 6,689,849; 7,009,015; and 7,244,794.

WO03014167 uses cyclic organosilicon compounds containing hetero-atom asan external electron donor in a catalyst system to prepare polypropylenewith higher melt flow rate (MFR). The silicon is embedded in a ringsystem, wherein only one hetero-atom is present. The propylene polymerprepared by using organosilane G with purity of 96% as an externalelectron donor is stated to have a narrow molecular weight distribution.No molecular weight distribution data are presented for the propylenepolymers prepared using other pure organosilanes (purity>95%) asexternal electron donors.

For certain applications, polymers with a wider molecular weightdistribution are desirable. Such polymers have a lower melt viscosity athigh shear rates. Many polymer fabrication processes operating with highshear rates, such as injection molding, oriented film and thermobondedfibers, could benefit from a lower viscosity product by improvingthroughput rates and reducing energy costs. Products with higherstiffness, as measured by flexural modulus, are important for injectionmolded, extruded, and film products, as the fabricated parts can bedown-gauged so that less material is needed to maintain productproperties. Broad molecular weight distribution is one of the importantcontributors to achieving high stiffness of polymeric materials.Therefore, it can be advantageous to tailor polymerization catalystsystems to obtain polymers with a wider molecular weight distribution.

Methods are described in JP-A-63-245408, JP-A-2-232207, andJP-A-4-370103 for the preparation of polymers with wide molecular weightdistribution obtained by polymerizing propylene in plural numbers ofpolymerization vessels or by multiple stage polymerizations. However,the disclosed operations are complicated with low production efficiency,and polymer structure and product quality are difficult to control.

There have been continuing efforts to tailor polymerization catalystsystems to enhance resin processability/extrusion characteristics viabroadening of polymer molecular weight distribution through utilizationof particular types of external electron donor systems. U.S. Pat. No.6,376,628 teaches bis(perhydroisoquinolino)dimethoxysilane compounds andU.S. Pat. No. 6,800,703 teaches vinyltrimethoxysilane ordicyclohexyldimethoxysilane compounds as external electron donor toproduce polypropylene with broad molecular weight distribution. U.S.Patent Application Publication 20060252894 discloses using mixed donorsystems comprising different silane compounds to produce polypropylenewith broadened molecular weight distribution.

There is a continuing need for developing catalyst systems that can beused to produce polyolefins, particularly polypropylene, with broadenedmolecular weight distribution. In addition to broadened molecular weightdistribution, desired catalyst systems should also offer goodpolymerization activity and hydrogen response. Furthermore, the catalystsystems should also offer a steady and wide operating window forcontrolling isotacticity of the resulting polymers based on end userapplication requirement.

SUMMARY OF THE INVENTION

This invention relates to cyclic organosilicon compounds that may beemployed as an electron donor for polymerization catalyst systems, topolymerization catalyst systems employing the cyclic organosiliconcompounds as an electron donor, to methods of making the polymerizationcatalyst systems, and to polymerization processes to producepolyolefins, particularly polypropylene, having broadened molecularweight distribution employing the polymerization catalyst systems.

In accordance with various aspects thereof, the present inventionrelates to a catalyst system for the polymerization or co-polymerizationof alpha-olefin comprising a solid Ziegler-Natta type catalystcomponent, a co-catalyst component, and an electron donor componentcomprising at least one cyclic organosilicon compound of the formula:

wherein Q₁ and Q₂, which may be identical or different, are each ahetero-atom selected from the group consisting of N, O, S, Si, B, P,with the proviso that Q₁ and Q₂ cannot both be N or both be O; whereinR₁ and R₂, which may be identical or different, are each ahydrocarbon-based substituent to Q₁ and Q₂, respectively; wherein m andn are independently 0-3; wherein R₃ is an aliphatic, alicyclic oraromatic group; wherein R₄ is a hydrocarbon group with 1 to 6 carbonatoms; and wherein R₅ is a bridging group with a backbone chain lengthbetween their two hetero-atoms Q₁ and Q₂ being 1-8 atoms, wherein thebackbone of said bridging group is selected from the group consisting ofaliphatic, alicyclic, and aromatic radicals. The present invention alsorelates to a composition containing a compound of the cyclicorganosilicon compound of the aforementioned formula. In accordance withvarious aspects thereof, the present invention also relates to a methodof polymerizing an alpha-olefin comprising polymerizing the alpha-olefinin the presence of the cyclic organosilicon compound of theaforementioned formula.

The features and advantages of the present invention will be readilyapparent to those skilled in the art. While numerous changes may be madeby those skilled in the art, such changes are within the spirit of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the mass spectrum of the product obtained in accordancewith the procedures of Example 1A.

FIG. 2 shows the ¹H-NMR spectrum of the product obtained in accordancewith the procedures of Example 1A.

FIG. 3 shows the GPC chromatographs of products obtained in accordancewith the procedures of Example 13 and Comparative Example 1.

FIG. 4 shows the GPC chromatographs of products obtained in accordancewith the procedures of Example 25 and Comparative Example 2.

FIG. 5 shows the mass spectrum of the product obtained in accordancewith the procedures of Example 8.

FIG. 6 shows the mass spectrum of the product obtained in accordancewith the procedures of Example 12.

DESCRIPTION OF PREFERRED EMBODIMENTS

This invention relates to cyclic organosilicon compounds that may beemployed as an electron donor for polymerization catalyst systems, topolymerization catalyst systems employing the cyclic organosiliconcompounds as an electron donor, to methods of making the polymerizationcatalyst systems, and to polymerization processes to producepolyolefins, particularly polypropylene, having broadened molecularweight distribution employing the polymerization catalyst systems.

In accordance with various embodiments, a class of organosiliconcompounds, which are useful as electron donors in polymerizationcatalyst systems for the production of polyolefins, particularlypolypropylene, are disclosed. These organosilicon compounds may be usedas either an internal electron donor or an external electron donor.Preferably, these organosilicon compounds are used as an externalelectron donor. Polymerization catalyst systems employing the cyclicorganosilicon compounds of the present invention may have an internalelectron donor, an external electron donor, or both an internal electrondonor and an external electron donor.

The organosilicon compounds of the present invention may be used aloneas a single constituent in an electron donor component of the catalystsystem or may be used in combination with one or more other compounds asan electron donor component of the catalyst system. If more than onecompound is used as the electron donor component, one or more of theconstituents may be organosilicon compounds of the present invention.

The organosilicon compounds of the present invention that may be used aselectron donors in polymerization catalyst systems are represented byFormula 1:

Q₁ and Q₂ may be identical or different and are each a hetero-atomselected from the group consisting of N, O, S, Si, B, and P, with theproviso that Q₁ and Q₂ cannot both be N or both be O. In preferredembodiments of the present invention, said Q₁ in Formula 1 is selectedfrom N, S, and P. In preferred embodiments of the present invention,said Q₂ in Formula 1 is selected from O, S, and P. Use of compounds inaccord with the present invention in a polymerization catalyst system isexpected to result in polymers having broader molecular weightdistribution than prior art electron donor compounds.

R₁ and R₂ may be identical or different and are each hydrocarbon-basedsubstituents to Q₁ and Q₂, respectively. The subscripts m and n areindependently 0 to 3, which one of ordinary skill in the art having thebenefit of this disclosure will recognize will depend on the valencestate of Q₁ and Q₂. The length and structure of R₁ and R₂ are notgenerally limited. In preferred embodiments of the present invention,said R₂ is small group such as hydrogen, methyl, or ethyl.

R₃ is an aliphatic, alicyclic or aromatic group, which may have one ormore C₁-C₂₀ linear or branched, saturated or unsaturated substituents.

R₄ is a hydrocarbon group with 1 to 6 carbon atoms. In preferredembodiments of the present invention, said R₄ is a methyl or ethylgroup.

R₅ is a bridging group with a backbone chain length between the twohetero-atoms Q₁ and Q₂ being 1-8 atoms. “Backbone chain length” in thiscontext refers to the atoms that are in the direct linkage between thetwo hetero-atoms Q₁ and Q₂. For example, if —CH₂— or —CH₂—CH2- is thebridging group then the associated backbone chain length is one and twoatoms, respectively, referring to the carbon atoms that provide thedirect linkage between the two hetero-atoms. Similarly, if the bridginggroup has the iso-structure, CH₃CHCH₂, then the associated backbonechain length is also two atoms.

The backbone of the bridging group is selected from the group consistingof aliphatic, alicyclic, and aromatic radicals. Preferably, the backboneof the bridging group is selected from the group consisting of aliphaticradicals, with or without unsaturation. The bridging group may have oneor more C₁-C₂₀ substituents (or side chains) extending off the backbonechain. The substituents may be branched or linear and may be saturatedor unsaturated. Similarly, the substituents may comprise aliphatic,alicyclic, and/or aromatic radicals.

One or more of carbon atom and/or hydrogen atom of R₁, R₂, R₃, R₄, andbridging group R₅, including any substituents thereof, may be replacedby a hetero-atom selected from the group consisting of N, O, S, Si, B,P, and halogen atoms. In various embodiments where such hetero-atomsubstitution occurs at R₃, the hetero-atom substitution is preferably atthe carbon atom that would have been bonded to the central Si atom.

In various embodiments of the present invention, two or more of said R₁,R₂, R₃, R₄, and bridging group R₅ may be linked to form one or moresaturated or unsaturated monocyclic or polycylic rings.

In preferred embodiments of the present invention, R₅ in Formula 1 is abridging group with chain length between two hetero-atoms Q₁ and Q₂being from 2 to 4 atoms.

In preferred embodiments of the invention, said R₄ in Formula 1 ismethyl or ethyl.

Examples of suitable ring structure organosilicon compounds of theFormula 1 include, but not are limited to:

The organosilicon compounds of the present invention may be used as acomponent in Ziegler-Natta type catalyst systems. Except for theinclusion of the organosilicon compounds of the present invention, theZiegler-Natta type catalyst systems, and methods for making suchcatalyst systems, which may be employed in accordance with the variousembodiments of the present invention are not generally limited. Typical,and acceptable, Ziegler-Natta type catalyst systems that may be used inaccordance with the present invention comprise (a) a solid Ziegler-Nattatype catalyst component and (b) a co-catalyst component. In accordancewith the various embodiments of the present invention, at least oneorganosilicon compound in accordance with the present invention is usedas an electron donor in the Ziegler-Natta type catalyst system. Aspreviously disclosed herein, these organosilicon compounds may be usedas either an internal electron donor or an external electron donor.Preferably, these organosilicon compounds are used as (c) an externalelectron donor.

Preferred solid Ziegler-Natta type catalyst component (a) includes solidcatalyst components comprising a titanium compound having at least aTi-halogen bond and an internal electron donor compound supported on ananhydrous magnesium-dihalide support. Such preferred solid Ziegler-Nattatype catalyst component (a) includes solid catalyst componentscomprising a titanium tetrahalide. A preferred titanium tetrahalide isTiCl₄. Alkoxy halides may also be used.

Acceptable internal electron donor compounds for the preparing solidZiegler-Natta type catalyst component (a) are not generally limited andinclude, but are not limited to, alkyl, aryl, and cycloalkyl esters ofaromatic acids, in particular the alkyl esters of benzoic acid andphthalic acid and their derivatives. Examples of such compounds includeethyl benzoate, n-butyl benzoate, methyl-p-toluate,methyl-p-methoxybenzoate, and diisobutylphthalate. Other common internalelectron donors, including alkyl or alkyl-aryl ethers, ketones, mono- orpolyamines, aldehydes, and P-compounds, such as phosphines andphosphoramides, may also be used. Finally, the organosilicon compoundsof the present invention may also be employed as an internal electronicdonor.

Acceptable anhydrous magnesium dihalides forming the support of thesolid Ziegler-Natta type catalyst component (a) are the magnesiumdihalides in active form that are well known in the art. Such magnesiumdihalides may be preactivated, may be activated in situ during thetitanation, may be formed in-situ from a magnesium compound, which iscapable of forming magnesium dihalide when treated with a suitablehalogen-containing transition metal compound, and then activated.Preferred magnesium dihalides are magnesium dichloride and magnesiumdibromide. The water content of the dihalides is generally less than 1%by weight.

The solid Ziegler-Natta type catalyst component (a) may be made byvarious methods. One such method consists of co-grinding the magnesiumdihalide and the internal electron donor compound until the productshows a surface area higher than 20 m²/g and thereafter reacting theground product with the Ti compound. Other methods of preparing solidZiegler-Natta type catalyst component (a) are disclosed in U.S. Pat.Nos. 4,220,554; 4,294,721; 4,315,835; 4,330,649; 4,439,540; 4,816,433;and 4,978,648. These methods are incorporated herein by reference.

In a typical solid Ziegler-Natta type catalyst component (a), the molarratio between the magnesium dihalide and the halogenated titaniumcompound is between 1 and 500 and the molar ratio between saidhalogenated titanium compound and the internal electron donor is between0.1 and 50.

Preferred co-catalyst component (b) include aluminum alkyl compounds.Acceptable aluminum alkyl compounds include aluminum trialkyls, such asaluminum triethyl, aluminum triisobutyl, and aluminum triisopropyl.Other acceptable aluminum alkyl compounds include aluminum-dialkylhydrides, such as aluminum-diethyl hydrides. Other acceptableco-catalyst component (b) include compounds containing two or morealuminum atoms linked to each other through hetero-atoms, such as:(C₂H₅)₂Al—O—Al(C₂H₅)₂(C₂H₅)₂Al—N(C₆H₅)—Al(C₂H₅)₂; and(C₂H₅)₂Al—O—SO₂—O—Al(C₂H₅)₂.

The olefin polymerization processes that may be used in accordance withthe present invention are not generally limited. For example, thecatalyst components (a), (b) and (c), when employed, may be added to thepolymerization reactor simultaneously or sequentially. It is preferredto mix components (b) and (c) first and then contact the resultantmixture with component (a) prior to the polymerization.

The olefin monomer may be added prior to, with, or after the addition ofthe Ziegler-Natta type catalyst system to the polymerization reactor. Itis preferred to add the olefin monomer after the addition of theZiegler-Natta type catalyst system.

The molecular weight of the polymers may be controlled in a knownmanner, preferably by using hydrogen. With the catalysts producedaccording to the present invention, molecular weight may be suitablycontrolled with hydrogen when the polymerization is carried out atrelatively low temperatures, e.g., from about 30° C. to about 105° C.This control of molecular weight may be evidenced by a measurablepositive change of the Melt Flow Rate.

The polymerization reactions may be carried out in slurry, liquid or gasphase processes, or in a combination of liquid and gas phase processesusing separate reactors, all of which may be done either by batch orcontinuously. The polyolefin may be directly obtained from gas phaseprocess, or obtained by isolation and recovery of solvent from theslurry process, according to conventionally known methods.

There are no particular restrictions on the polymerization conditionsfor production of polyolefins by the method of the invention, such asthe polymerization temperature, polymerization time, polymerizationpressure, monomer concentration, etc. The polymerization temperature isgenerally from 40-90° C. and the polymerization pressure is generally 1atmosphere or higher.

The Ziegler-Natta type catalyst systems of the present invention may beprecontacted with small quantities of olefin monomer, well known in theart as prepolymerization, in a hydrocarbon solvent at a temperature of60° C. or lower for a time sufficient to produce a quantity of polymerfrom 0.5 to 3 times the weight of the catalyst. If such aprepolymerization is done in liquid or gaseous monomer, the quantity ofresultant polymer is generally up to 1000 times the catalyst weight.

The Ziegler-Natta type catalyst systems of the present invention areuseful in the polymerization of olefins, including but not limited tohomopolymerization and copolymerization of alpha olefins. Suitableα-olefins that may be used in a polymerization process in accordancewith the present invention include olefins of the general formulaCH₂═CHR, where R is H or C₁₋₁₀ straight or branched alkyl, such asethylene, propylene, butene-1, pentene-1,4-methylpentene-1 and octene-1.While the Ziegler-Natta type catalyst systems of the present inventionmay be employed in processes in which ethylene is polymerized, it ismore desirable to employ the Ziegler-Natta type catalyst systems of thepresent invention in processes in which polypropylene or higher olefinsare polymerized. Processes involving the homopolymerization orcopolymerization of propylene are preferred.

To facilitate a better understanding of the present invention, thefollowing examples of certain aspects of some embodiments are given. Inno way should the following examples be read to limit, or define, theentire scope of the invention.

EXAMPLES

The catalyst components and properties of polymers in the examples weremeasured according to the following methods:

¹H-NMR and GC/MS were used to characterize the organosilane compounds.

Organosilicon compounds analyses were conducted by GC/MS (GasChromatograph with Mass Spectrometry) with Chemstation software G1701BAversion B.01.00 for data handling.

Instruments used in analyses are listed as follows:

-   -   Gas Chromatography: Agilent 5890 Series II Plus    -   Injector: Agilent 7673 Auto Injector    -   Mass Spectra Detector: Agilent 5989B

The Column was a Phenomenex ZB-5 ms 5% Polysilarylene and 95%Polydimethylsiloxane with dimensions of 30 meters length, 0.25 mm ID,and 1.00 micron film thickness. The chromatographic conditions were asfollows: GC inlet temperature 250° C.; oven temperature program set 50°C. initially, to 130° C. at 35° C. per minute, and to 320° C. at 12° C.per minute and held for 6 minutes; column flow rate of 1.0 ml/min; asplit flow rate of 1:75; injection volume of 1.0 micro liter; and massspectra scan range 50-650 amu. The mass spectra were obtained from theTIC mode (total ion chromatogram) after GC separation.

The following analytical methods were used to characterize the polymer.

Heptane Insolubles (HI): The residuals of PP after extracted withboiling heptane for 6 hours.

Melt Flow Rate: ASTM D-1238, determined at 230° C., under the load of2.16 kg.

Tm: ASTM D-3417, determined by DSC (Manufacturer: TA Instrument, Inc.;Model: DSC Q1000).

Molecular weight (Mn and Mw): The weight average molecular weight (Mw),number average molecular weight (Mn), and molecular weight distribution(Mw/Mn) of polymers were obtained by gel permeation chromatography onWaters 2000GPCV system using Polymer Labs Plgel 10 um MIXED-B LS 300×7.5mm columns and 1,2,4,4-trichlorobenzene (TCB) as mobile phase. Themobile phase was set at 0.9 ml/min, and temperature was set at 145° C.Polymer samples are heated at 150° C. for two hours. Injection volumewas 200 microliters. External standard calibration of polystyrenestandards was used to calculate the molecular weight.

Specimens for below tests were injection molded according to theconditions specified in ASTM D-4101.

-   -   Flexural Modulus (1.3 mm/min), 1% Secant: ASTM D-790.    -   Tensile strength at yield (50 mm/min): ASTM D-638.    -   Elongation at yield (50 mm/min): ASTM D-638    -   Notched IZOD Impact strength@73° F.: ASTM D-256.    -   HDT@66 psi: ASTM D-648.    -   Rockwell Hardness: ASTM D-785

Unless otherwise indicated, all reactions were conducted under an inertatmosphere.

Organosilicon Compound Preparation Example 1A

This example illustrates an organosilicon compound in accordance withthe present invention and a method of preparing the same.

(a) Preparation of 3-tert-Butyl-2chloro-2-isobutyl-[1,3,2]oxazasilolidine

2-(tert-Butylamino)ethanol (0.125 mmol, 99%, from Aldrich) was dissolvedin THF (100 ml, anhydrous, from Aldrich) in a 250 ml flask with aice-water bath, and while stirring n-butyllithium (100 ml of a 2.5 Msolution in hexanes, from Aldrich) was added dropwise over a period of40 minutes. Then, the ice-water bath was removed and the reactionmixture was stirred for 20 minutes at room temperature. A pale yellowclear solution was obtained.

While stirring, the obtained solution was added dropwise into a 500 mlflask containing 0.125 mol isobutyltrichlorosilane (from Gelest) and 250ml Heptane cooled by an ice-water bath. The resultant reaction mixturewas stirred for 30 minutes and thereafter the ice-water bath was removedand the reaction was carried on at room temperature for 4 hours.Stirring was stopped and the reaction mixture was kept still overnightto precipitate the solid byproduct. The supernatant clear solution wastransferred into a flask and condensed under reduced pressure to removethe solvent constituents, such as THF, and subsequently distilled andpurified to restore the target product. The target product was a liquidwith colorless transparent appearance.

(b) Preparation of3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine

0.05 mol Lithium methoxide, 300 ml THF and 0.05 mol above obtainedproduct were orderly added into a 500 ml flask. Stirring was started andthe reaction temperature was brought up to 65° C. with an oil bath overa period of 30 minutes. The reaction was carried out at 65° C. for 8hours. Thereafter, THF was removed at 25° C. under reduced pressure, andthen 250 ml Heptane was added into the 500 ml flask. Stirring wasstopped and the vessel was kept still overnight to precipitate the solidbyproduct. The supernatant clear solution was transferred into a flaskand condensed under reduced pressure to remove the Heptane, andsubsequently distilled and purified to restore the target product. Thetarget product was a liquid with colorless transparent appearance, whichhas a GC purity of 97%. The target product was identified by gas-masschromatography, of which mass spectrum is shown in FIG. 1, and NMR isshown in FIG. 2.

Example 1B

This example illustrates another method of preparing3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine.

Preparation of 3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine

2-(tert-Butylamino)ethanol (0.08 mol, 99%, from Aldrich) was dissolvedin THF (100 ml, anhydrous, from Aldrich) in a 250 ml flask with anice-water bath, and while stirring n-butyllithium (100 ml of a 1.6 Msolution in hexanes, from Aldrich) was added dropwise over a period ofabout 30 minutes. Then, the ice-water bath was removed and stirring ofthe reaction mixture was maintained for 20 minutes at room temperature.

The above prepared reaction mixture was added into a 500 ml flaskcontaining a stirring mixture of 14.3 g isobutyltrimethoxysilane (fromGelest), 120 ml heptane and 120 ml THF over a period of 15 minutes atroom temperature. Thereafter, the reaction temperature was raised to 60°C. with an oil-bath. The reaction was carried out at 60° C. for 5 hourswith stirring. Stir was stopped and the resultant reaction mixture waskept still at room temperature overnight to precipitate the solidbyproduct. The supernatant clear solution was transferred into a flaskand condensed under reduced pressure to remove the solvents, andsubsequently distilled and purified to restore the target product. Thetarget product was a liquid with colorless transparent appearance, whichhad a GC purity of 97%.

Examples 2 to 8

The procedure and ingredients of Example 1A were repeated except thatisobutyltrichlorosilane was replaced by the chemicals (RSiCl₃) shown inTable 1.

TABLE 1 Example RSiCl3 Final Product 2 Isooctyltrichlorosilane3-tert-Butyl-2-methoxy-2- (2,4,4-trimethyl-pentyl)-[1,3,2]oxazasilolidine 3 t-Butyltrichlorosilane 2,3-Di-tert-butyl-2-methoxyl- [1,3,2]oxazasilolidine 4 Cyclopentyltrichlorosilane3-tert-Butyl-2-cyclopentyl- 2-methoxy- [1,3,2]oxazasilolidine 5Cyclohexyltrichlorosilane 3-tert-Butyl-2-cyclohexyl- 2-methoxy-[1,3,2]oxazasilolidine 6 5- 2-Bicyclo[2.2.1]hept-5-(Bicycloheptenyl)trichlorosilane en-2- yl-3-tert-butyl-2-methoxy-[1,3,2]oxazasilolidine 7 Phenyltrichlorosilane 3-tert-Butyl-2-methoxy-2-phenyl- [1,3,2]oxazasilolidine

Example 8 Preparation of 1-Trimethoxysilyl-2-methyl-piperidine

0.25 mol 2-Methylpiperidine and 80 ml THF were added into a 250 mlflask. The flask was put in an ice-water bath. Thereafter, whilestirring, 100 ml Butyllithium solution (2.5 M in Hexanes) was addeddropwise into the 250 ml flask over a period of 40 minutes. Then theice-water bath was removed. Stirring of the reaction mixture wasmaintained for 1 hour at room temperature. A clear solution wasobtained.

0.25 mol tetramethyl orthosilicate and 250 ml Heptane were added into a500 ml flask. The flask was put in an ice-water bath. Thereafter, whilestirring, the above obtained solution in the 250 ml flask was addeddropwise into the 500 ml flask over a period of 60 minutes. Then theice-water bath was removed. Stirring of the reaction mixture wasmaintained for 5 hours at room temperature. Stirring was stopped and thereaction mixture was kept still overnight to precipitate the solidby-product. The supernatant clear solution was transferred into a flaskand condensed under reduced pressure to remove the solvent constituents,such as THF, and subsequently distilled and purified to restore thetarget product. The target product was a liquid with colorlesstransparent appearance.

b) Preparation of1-(3-tert-Butyl-2-methoxy-[1,3,2]oxazasilolidin-2-yl)-2-methyl-piperidine

2-(tert-Butylamino)ethanol (0.08 mmol, 99%, from Aldrich) was dissolvedin THF (100 ml, anhydrous, from Aldrich) in a 250 ml flask with aice-water bath, and while stirring n-butyllithium (100 ml of a 1.6 Msolution in hexanes, from Aldrich) was added dropwise over a period of40 minutes. Then the ice-water bath was removed. Stirring of thereaction mixture was maintained for 2 hours at room temperature. A paleyellow clear solution was obtained.

While stirring, over a period of 60 minutes the obtained solution wasadded dropwise into a 500 ml flask containing 0.08 mol silane compoundprepared in a), 120 ml THF, and 120 ml Heptane cooled by an ice-waterbath. Thereafter, the ice-water bath was removed and the reactiontemperature was raised to 70° C. The reaction was carried on at thistemperature for 5 hours. Then the stir was stopped and the reactionmixture was kept still overnight to precipitate the solid byproduct. Thesupernatant clear solution was transferred into a flask and condensedunder reduced pressure to remove the solvent constituents such as THF,and subsequently distilled and purified to restore the target product.The target product was a liquid with colorless transparent appearance,which has a GC purity of 98%. The target product was identified bygas-mass chromatography, of which mass spectrum is shown in FIG. 5.

Examples 9 to 11

The procedure and ingredients of Example 8 were repeated except that2-methylpiperidine was replaced by the amine compounds shown in Table 2.

TABLE 2 Example Amine compound Final Product 9 3-Methylpiperidine1-(3-tert-Butyl-2-methoxy- [1,3,2]oxazasilolidin-2-yl)-3-methyl-piperidine 10 3,5-Dimethylpiperidine1-(3-tert-Butyl-2-methoxy- [1,3,2]oxazasilolidin-2-yl)-3,5-dimethyl-piperidine 11 Diethylamine (3-tert-Butyl-2-methoxy-[1,3,2]oxazasilolidin-2- yl)-diethyl-amine

Example 12 Preparation of3-tert-Butyl-2,2-diethoxy-[1,3,2]oxazasilolidine

2-(tert-Butylamino)ethanol (0.08 mmol, 99%, from Aldrich) was dissolvedin THF (100 ml, anhydrous, from Aldrich) in a 250 ml flask with aice-water bath, and while stirring n-butyllithium (100 ml of a 1.6 Msolution in hexanes, from Aldrich) was added dropwise over a period of40 minutes. Then the ice-water bath was removed. Stirring of thereaction mixture was continued for 2 hours at room temperature. A paleyellow clear solution was obtained.

While stirring, over a period of 60 minutes the obtained solution wasadded dropwise into a 500 ml flask containing 0.08 molDiethoxydichlorosilane (90%, from Gelest) 250 ml Heptane cooled by anice-water bath. Thereafter, the ice-water bath was removed and thereaction was carried on at room temperature for 5 hours. Then, stirringwas stopped and the reaction mixture was kept still overnight toprecipitate the solid byproduct. The supernatant clear solution wastransferred into a flask and condensed under reduced pressure to removethe solvent constituents, such as THF, and subsequently distilled andpurified to restore the target product. The target product was a liquidwith colorless transparent appearance, which has a GC purity of 96%. Thetarget product was identified by gas-mass chromatography, of which massspectrum is shown in FIG. 6.

POLYMERIZATION EXAMPLES Example 13

A bench scale 2-liter reactor was used. The reactor was first preheatedto at least 100° C. with a nitrogen purge to remove residual moistureand oxygen. The reactor was thereafter cooled to 50° C.

Under nitrogen, 1 liter dry hexane was introduced into the reactor. Whenreactor temperature was about 50° C., 2.5 ml triethyl aluminum (1.0M),2.4 ml 3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine (0.5 M inheptane) and then 30 mg Toho 53-009 catalyst (available from TohoCatalyst Ltd.) were added to the reactor. The pressure of the reactorwas raised to 28.5 psig at 50° C. by introducing nitrogen. 8 psig.Hydrogen in a 150 cc vessel was flushed into the reactor with propylene.

The reactor temperature was then raised to 70° C. The total reactorpressure was raised to and controlled at 90 psig by continuallyintroducing propylene into the reactor and the polymerization wasallowed to proceed for 1 hour. After polymerization, the reactor wasvented to reduce the pressure to 0 psig and the reactor temperature wascooled down to 50° C.

The reactor was then opened. 500 ml methanol was added to the reactorand the resulting mixture was stirred for 5 minutes then filtered toobtain the polymer product. The obtained polymer was vacuum dried at 80°C. for 6 hours. The polymer was evaluated for melt flow rate (MFR),percent heptane insolubles (% HI), and molecular weight distribution(Mw/Mn). The activity of catalyst (AC) was also measured. The resultsare shown below in Table 3 and FIG. 3.

Comparative Example 1

The polymerization were performed in the same manner as in Example 13except that 2.4 ml3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine (0.5M inheptane) was replaced by 0.8 ml Diisopropyldimethoxysilane (0.5M inheptane). The results are shown in Table 3 and FIG. 3.

Examples 14 to 24

The polymerization were performed in the same manner as in Example 13except that 3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine wasreplaced by the organosilicon compounds as shown in Table 3. The resultsare shown below in Table 3.

TABLE 3 AC MFR HI Example Organosilicon compounds (gPP/gCat · h) (g/10min) (%) Mw/Mn Ex. 13 3-tert-Butyl-2-isobutyl-2methoxy- 5129 2.1 98.45.6 [1,3,2]oxazasilolidine Ex. 14 3-tert-Butyl-2-methoxy-2-(2,4,4- 40132.5 97.3 5.6 trimethyl-pentyl)-[1,3,2]oxazasilolidine Ex. 152,3-Di-tert-butyl-2-methoxyl- 5567 1.3 98.5 5.1 [1,3,2]oxazasilolidineEx. 16 3-tert-Butyl-2-cyclopentyl-2-methoxy- 4843 2.1 98 5.5[1,3,2]oxazasilolidine Ex. 17 3-tert-Butyl-2-cyclohexyl-2-methoxy- 38652.2 97.1 5.7 [1,3,2]oxazasilolidine Ex. 182-Bicyclo[2.2.1]hept-5-en-2-yl-3-tert- 3967 1.2 98.4 5.5butyl-2-methoxy-[1,3,2]oxazasilolidine Ex. 193-tert-Butyl-2-methoxy-2-phenyl- 2649 2.1 97.9 5.6[1,3,2]oxazasilolidine Ex. 20 1-(3-tert-Butyl-2-methoxy- 3964 2.7 97.8 6[1,3.2]oxazasilolidin-2-yl)-2-methyl- piperidine Ex. 211-(3-tert-Butyl-2-methoxy- 3229 2.5 98.3 6.1[1,3,2]oxazasilolidin-2-yl)-3-methyl- piperidine Ex. 221-(3-tert-Butyl-2-methoxy- 4311 2.4 97 6.1[1,3,2]oxazasilolidin-2-yl)-3,5-dimethyl- piperidine Ex. 23(3-tert-Butyl-2-methoxy- 3562 2.1 97.3 6[1,3,2]oxazasilolidin-2-yl)-diethyl-amine Ex. 243-tert-Butyl-2,2-diethoxy- 2777 17.9 96 5 [1,3,2]oxazasilolidine Comp.Diisopropyldimethoxysilane 4845 2 99 4.5 Ex. 1

Example 25

A 10-liter reactor was used. The reactor was purged with nitrogen at 90°C. for 1 hour and then cooled down to 30° C.

The reactor was vacuumed to remove nitrogen. Then 3.6 kg propylene, 12.5liter hydrogen, 50 ml triethyl aluminum hexane solution (0.6M) and 4.5ml 3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine heptanesolution (0.5M) were fed into the 10-liter reactor. Stirring wasstarted. Thereafter, 60 mg Lynx 1010 catalyst (available from BASFCatalyst LLC) in a tube connected to the 10-liter reactor was flushedinto the reactor with 0.2 kg liquid propylene. The prepolymerization wascarried out at 30° C. for 15 minutes. Then, the temperature was raisedto 80° C. over a period of 10 minutes and the polymerization was run atthis temperature for 1 hour. After polymerization, unreacted propylenewas vented out, and the temperature of the reactor was lowered to roomtemperature.

The polymer powder obtained in the polymerization was admixed with anadditive mixture in the granulation step. Granulation was carried outusing a twinscrew extruder ZSK 30 from Werner & Pfleiderer at a melttemperature of 230° C. The polymer composition obtained contained 0.035%by weight of an antioxidant (trade name: Anox 20, from ChemturaCorporation), 0.075% by weight of an antioxidant (trade name: AnoxBB021, from Chemtura Corporation), and 0.1% by weight of calciumstearate (from Baerloch USA). The properties of the polymer compositionare shown in Table 4 and FIG. 4. The data was determined on the polymercomposition after addition of additives and granulation or on testspecimens produced therefrom. The activity of catalyst (AC) was alsomeasured and shown in Table 4.

Comparative Example 2

The polymerization was performed in the same manner as in Example 25except that the hydrogen added was 7.1 liter and the silane3-tert-Butyl-2-isobutyl-2methoxy-[1,3,2]oxazasilolidine was replaced bycyclohexylmethyldimethoxysilane (C-donor). The results are shown inTable 4 and FIG. 4

TABLE 4 Ex. No Ex. 13 C. Ex. 2 Donor 3-tert-Butyl-2-isobutyl- C-donor2methoxy- [1,3,2]oxazasilolidine Activity (gPP/gCat.) 27438 23000 Mw/Mn5.9 4.1 MI (g/10 min) 6.5 6.2 Flex Modulus (Kpsi) 227 213 TensileStrength @ Yield (psi) 5337 5294 Impact Strength (ft lb/in) 0.5 0.5Elongation @ Yield (%) 9 8 Rockwell Hardness 107 105 HDT@66 psi, ° C.110.8 107.4 Tm (° C.) 164.98 164.01 Crystallization Temp, ° C. 120.82117.1

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered ormodified and all such variations are considered within the scope andspirit of the present invention. Whenever a numerical range with a lowerlimit and an upper limit is disclosed, any number falling within therange is specifically disclosed. Moreover, the indefinite articles “a”or “an”, as used in the claims, are defined herein to mean one or morethan one of the element that it introduces.

1. A catalyst system for the polymerization or co-polymerization ofalpha-olefin comprising a solid Ziegler-Natta type catalyst component, aco-catalyst component, and an electron donor component comprising atleast one cyclic organosilicon compound of the formula:

wherein Q₁ and Q₂ are each a hetero-atom independently selected from thegroup consisting of N, O, S, Si, B, P, with the proviso that Q₁ and Q₂cannot both be N or both be O; wherein R₁ and R₂ are independently eacha hydrocarbon-based substituent to Q₁ and Q₂, respectively; wherein mand n are independently 0-3; wherein R₃ is an aliphatic, alicyclic oraromatic group; wherein R₄ is a hydrocarbon group with 1 to 6 carbonatoms; and wherein R₅ is a bridging group with a backbone chain lengthbetween the two hetero-atoms Q₁ and Q₂ being 1-8 atoms, wherein thebackbone of said bridging group is selected from the group consisting ofaliphatic, alicyclic, and aromatic radicals.
 2. A catalyst systemaccording to claim 1, wherein R₃ comprises one or more C₁-C₂₀ linear orbranched substituents.
 3. A catalyst system according to claim 1,wherein R₅ comprises a C₁-C₂₀ linear or branched substituent.
 4. Acatalyst system according to claim 1, wherein two or more of said R₁,R₂, R₃, R₄, and R₅ are linked to form one or more saturated orunsaturated monocyclic or polycylic rings.
 5. A catalyst systemaccording to claim 1, wherein said backbone chain length of the bridginggroup R₅ is from 2 to 4 atoms.
 6. A catalyst system according to claim1, wherein said hetero-atom Q₁ in Formula 1 is selected from the groupconsisting of N, S, and P.
 7. A catalyst system according to claim 1,wherein said hetero-atom Q₂ in Formula 1 is O.
 8. A catalyst systemaccording to claim 1, wherein at least one of a carbon atom or hydrogenatom of R₁, R₂, R₃, R₄, or R₅ is replaced with a hetero-atom selectedfrom the group consisting of N, O, S, Si, B, P, and halogen atoms.
 9. Acatalyst system according to claim 1, wherein said R₄ is a methyl group.10. A catalyst system according to claim 1, wherein said R₄ is an ethylgroup.
 11. A composition comprising a compound of the formula:

wherein Q₁ and Q₂ are each a hetero-atom independently selected from thegroup consisting of N, O, S, Si, B, P, with the proviso that Q₁ and Q₂cannot both be N or both be O; wherein R₁ and R₂ are independently eacha hydrocarbon-based substituent to Q₁ and Q₂, respectively; wherein mand n are independently 0-3; wherein R₃ is an aliphatic, alicyclic oraromatic group; wherein R₄ is a hydrocarbon group with 1 to 6 carbonatoms; and wherein R₅ is a bridging group with a backbone chain lengthbetween the two hetero-atoms Q₁ and Q₂ being 1-8 atoms, wherein thebackbone of said bridging group is selected from the group consisting ofaliphatic, alicyclic and aromatic radicals.
 12. A composition accordingto claim 11, wherein R₃ comprises one or more C₁-C₂₀ linear or branchedsubstituents.
 13. A composition according to claim 11, wherein saidbridging group R₅ comprises a C₁-C₂₀ linear or branched substituent. 14.A composition according to claim 11, wherein two or more of said R₁, R₂,R₃, R₄, and R₅ are linked to form one or more saturated or unsaturatedmonocyclic or polycylic rings.
 15. A method for polymerizing analpha-olefin comprising polymerizing alpha-olefin in the presence of asolid Ziegler-Natta type catalyst component, a co-catalyst component,and an electron donor component comprising at least one cyclicorganosilicon compound of the formula:

wherein Q₁ and Q₂ are each a hetero-atom independently selected from thegroup consisting of N, O, S, Si, B, P, with the proviso that Q₁ and Q₂cannot both be N or both be O; wherein R₁ and R₂ are independently eacha hydrocarbon-based substituent to Q₁ and Q₂, respectively; wherein mand n are independently 0-3; wherein R₃ is an aliphatic, alicyclic oraromatic group; wherein R₄ is a hydrocarbon group with 1 to 6 carbonatoms; and wherein R₅ is a bridging group with a backbone chain lengthbetween their two hetero-atoms Q₁ and Q₂ being 1-8 atoms, wherein thebackbone of said bridging group is selected from the group consisting ofaliphatic, alicyclic and aromatic radicals.
 16. A method according toclaim 15, wherein R₃ comprises one or more C₁-C₂₀ linear or branchsubstituents.
 17. A method according to claim 15, wherein R₅ comprises aC₁-C₂₀ linear or branch substituent.
 18. A method according to claim 15,wherein two or more of said R₁, R₂, R₃, and R₅ are linked to form one ormore saturated or unsaturated monocyclic or polycylic rings.